1. Field of the Inventions
The present inventions relate to watercraft propulsion systems and operation control methods therefor, and more particularly, to hybrid type watercraft propulsion systems which can include an engine and an electric motor working as drive power sources for a propeller.
2. Description of the Related Art
Known designs for hybrid type watercraft propulsion systems which include an engine and an electric motor working as drive power sources for a propeller are disclosed in Japanese Patent Documents JP-A-2004-257294 and JP-A-2006-36086. Japanese Patent Document JP-A-2004-257294 discloses a system in which the driving force by an electric motor assists the driving force by an engine to drive a power transmitting device.
Japanese Patent Document JP-A-2006-36086 discloses a system with a throttle grip that is pivotally operable and is attached to a handlebar and a control switch disposed adjacent to the throttle grip. Rotational directions of the electric motor can be controlled by operating the control switch, and rotational speeds of the electric motor and engine speeds of the engine are adjustable in response to a rotational operation of the throttle grip.